PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       wctomb — convert a wide-character code to a character

SYNOPSIS

       #include <stdlib.h>

       int wctomb(char *s, wchar_t wchar);

DESCRIPTION

       The functionality described on this reference page is aligned with the ISO C standard. Any
       conflict between the requirements described here and the ISO C standard is  unintentional.
       This volume of POSIX.1‐2008 defers to the ISO C standard.

       The  wctomb()  function  shall  determine  the  number  of  bytes  needed to represent the
       character corresponding to the wide-character code whose value  is  wchar  (including  any
       change in the shift state). It shall store the character representation (possibly multiple
       bytes and any special bytes to change shift state) in the array object pointed to by s (if
       s  is  not  a  null pointer). At most {MB_CUR_MAX} bytes shall be stored. If wchar is 0, a
       null byte shall be stored, preceded by any shift sequence needed to  restore  the  initial
       shift state, and wctomb() shall be left in the initial shift state.

       The  behavior of this function is affected by the LC_CTYPE category of the current locale.
       For a state-dependent encoding, this function shall be placed into its initial state by  a
       call for which its character pointer argument, s, is a null pointer. Subsequent calls with
       s as other than a null pointer shall cause the  internal  state  of  the  function  to  be
       altered  as necessary. A call with s as a null pointer shall cause this function to return
       a non-zero value if encodings  have  state  dependency,  and  0  otherwise.  Changing  the
       LC_CTYPE category causes the shift state of this function to be unspecified.

       The wctomb() function need not be thread-safe.

       The  implementation  shall behave as if no function defined in this volume of POSIX.1‐2008
       calls wctomb().

RETURN VALUE

       If s is a null pointer, wctomb()  shall  return  a  non-zero  or  0  value,  if  character
       encodings,  respectively,  do or do not have state-dependent encodings. If s is not a null
       pointer, wctomb() shall return −1 if the value of wchar does not  correspond  to  a  valid
       character,  or  return  the number of bytes that constitute the character corresponding to
       the value of wchar.

       In no case shall the value returned be greater than the value of the {MB_CUR_MAX} macro.

ERRORS

       The wctomb() function shall fail if:

       EILSEQ An invalid wide-character code is detected.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       mblen(), mbtowc(), mbstowcs(), wcstombs()

       The Base Definitions volume of POSIX.1‐2008, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1,  2013  Edition,  Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013  by  the
       Institute  of  Electrical  and  Electronics  Engineers,  Inc and The Open Group.  (This is
       POSIX.1-2008 with the  2013  Technical  Corrigendum  1  applied.)  In  the  event  of  any
       discrepancy  between  this  version and the original IEEE and The Open Group Standard, the
       original IEEE and The Open Group Standard is the referee document. The  original  Standard
       can be obtained online at http://www.unix.org/online.html .

       Any  typographical  or  formatting errors that appear in this page are most likely to have
       been introduced during the conversion of the source files to man page  format.  To  report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .